<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="root"></div>
</body>

</html>
<script src="https://unpkg.com/vue@next"></script>
<script>
    // computed 计算属性
    const app = Vue.createApp({
        setup() {
            const {reactive,computed} = Vue;
            const countObj = reactive({count:0});
            const handleClick=()=>{
                countObj.count+=1;
            }
            let countAddFive=computed({
                get:()=>{
                    return countObj.count + 5;
                },
                set:(param)=>{
                    countObj.count=param-5;
                }
            })
            setTimeout(()=>{
                countAddFive.value=100;
            },3000)
            return {
                countObj,countAddFive,handleClick
            }
        },
        template: `
        <div>
            <span @click="handleClick">{{countObj.count}}</span> -- {{countAddFive}}
        </div>
        `,
    })
    const vm = app.mount('#root')
</script>